Materialism regards atoms as the bricks of which the material universe, the house we inhabit, is built. Sir William Thomson (Lord Kelvin) estimates that, if a drop of water were magnified to the size of our earth, the atoms of which it consists would certainly appear larger than boy’s marbles, and yet would be smaller than billiard balls. Of these atoms, all things, visible and invisible, are made. Mind, with all its activities, is a combination or phenomenon of atoms. “Man ist was er iszt: ohne Phosphor kein Gedanke”—“One _is_ what he _eats_: without phosphorus, no thought.” Ethics is a bill of fare; and worship, like heat, is a mode of motion. Agassiz, however, wittily asked: “Are fishermen, then, more intelligent than farmers, because they eat so much fish, and therefore take in more phosphorus?” It is evident that much is here attributed to atoms which really belongs to force. Deprive atoms of force, and all that remains is extension, which = space = zero. Moreover, “if atoms _are_ extended, they cannot be ultimate, for extension implies divisibility, and that which is conceivably divisible cannot be a philosophical ultimate. But, if atoms _are not_ extended, then even an infinite multiplication and combination of them could not produce an extended substance. Furthermore, an atom that is neither extended substance nor thinking substance is inconceivable. The real ultimate is force, and this force cannot be exerted by nothing, but, as we shall hereafter see, can be exerted only by a personal Spirit, for this alone possesses the characteristics of reality, namely, definiteness, unity, and activity.”